Phys.org February 28, 2024 An ideal integrated microwave photonics (MWP) processing platform should have both an efficient and high-speed electro-optic modulation block to faithfully perform microwave–optic conversion at low power and a low-loss functional photonic network to implement various signal-processing tasks, and large-scale, low-cost manufacturability. An international team of researchers (Hong Kong, UK, China) demonstrated such an engine based on a 4-inch wafer-scale thin-film lithium niobate platform. It could perform multipurpose tasks with processing bandwidths of up to 67 GHz at CMOS-compatible voltages. They achieved ultrafast analogue computation. They demonstrated these functions to show three proof-of-concept applications: solving ordinary differential equations, […]
Tag Archives: Signal processing
New optical switch could lead to ultrafast all-optical signal processing
Phys.org August 1, 2022 The weak native nonlinearity of most nanophotonic platforms has imposed barriers for the use of optical nonlinear functions for applications in integrated photonics, including all-optical information processing, photonic neural networks, and on-chip ultrafast light sources, by necessitating large driving energies, high-Q cavities, or integration with other materials with stronger nonlinearity. A team of researchers in the US (Caltech, Cornell University) has effectively utilized the strong and instantaneous quadratic nonlinearity of lithium niobate nanowaveguides for the realization of cavity-free all-optical switching. By simultaneous engineering of the dispersion and quasi-phase matching, they designed and demonstrated a nonlinear splitter […]
New method can improve explosion detection
Science Daily July 22, 2022 Explosions produce infrasound waves capable of propagating globally, but the spatio-temporal variability of the atmosphere makes detecting events difficult. Machine learning (ML) is well-suited to identify the subtle and nonlinear patterns in explosion infrasound signals, but a previous lack of ground-truth data inhibited training of generalized models. A team of researchers in the US (University of Alaska, Air Force, University of Mississippi, Los Alamos National Laboratory) has developed a physics-based method that propagates infrasound sources through realistic atmospheres to create 28,000 synthetic events, which are used to train ML classifiers. A simple artificial neural network […]
World’s smallest, best acoustic amplifier emerges from 50-year-old hypothesis
Nanowerk June 2, 2021 Researchers at Sandia National Laboratory have developed a heterogeneously integrated acoustoelectric material platform consisting of a 50 nm indium gallium arsenide epitaxial semiconductor film in direct contact with a 41° YX lithium niobate piezoelectric substrate. They demonstrated three of the main components of an all-acoustic radiofrequency signal processor: passive delay line filters, amplifiers, and circulators. Heterogeneous integration allows for simultaneous, independent optimization of the piezoelectric-acoustic and electronic properties, leading to the highest performing surface acoustic wave amplifiers in terms of gain per unit length and DC power dissipation. They described how the remaining components of an all-acoustic […]
Perfect transmission through barrier using sound
Science Daily December 23, 2020 Tunneling plays an essential role in many branches of physics and has found important applications. It is theoretically proposed that Klein tunneling occurs when, under normal incidence, quasiparticles exhibit unimpeded penetration through potential barriers independent of their height and width. A team of researchers in the US (UC Berkeley, Georgia Institute of Technology, Lawrence Berkeley National Laboratory) created a phononic heterojunction by sandwiching two types of artificial phononic crystals with different Dirac point energies. They demonstrated direct observation of Klein tunneling as shown by the key feature of unity transmission. Their experiment reveals that Klein […]
Engineers demonstrate metamaterials that can solve equations
Science Daily March 22, 2019 Signal processing of light waves can be used to represent certain mathematical functions and to perform computational tasks on signals or images in an analog fashion using complex systems of bulk optical elements such as lenses, filters, and mirrors. Researchers at the University of Pennsylvania have demonstrated that specially designed nanophotonic structures can take input waveforms encoded as complex mathematical functions, manipulate them, and provide an output that is the integral of the functions. The results, demonstrated for microwaves, provide a route to develop chip-based analog optical computers and computing elements… read more. TECHNICAL ARTICLE
A phonon laser operating at an exceptional point
Phys.org July 20, 2018 Exceptional points (EP) are singularities in the energy functions of a physical system at which two light modes coalesce to produce unusual effects. Understanding the mechanisms responsible for linewidth broadening will enable laser resources with new capabilities. An international of researchers led by the US used an optomechanical system with two coupled silica whispering-gallery-mode microresonators to exploit the interplay between gain and loss to tune a phonon laser to an EP. The team provided direct experimental evidence to show complete overlap of optical supermodes at EP, and that EP-enhanced optical noise can be transferred directly to […]